@jasonkoebler
The list of apps which were supplying geolocation data to Gravy is here :

https://docs.google.com/spreadsheets/u/0/d/1Ukgd0gIWd9gpV6bOx2pcSHsVO6yIUqbjnlM4ewjO6Cs/htmlview?usp=sharing&pli=1

The high-download ones are Outlook and all Candy Crush games.

I'd suggest (for Android) going into Settings -> Location -> App Location Permissions , and remove the Location permission from all apps unless necessary (e.g. driving map/nav); and then check any apps you *do* need against the list above.